JPH11342509A - Production of thermoplastic elastomer composition for powder molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a thermoplastic elastomer compsn. for powder molding excellent in melt flow proprties necessary for powder slush molding, low in melt viscosity, excellent in tensile strength and not generating stickiness or gloss on the surface of a molded sheet by heat ageing. SOLUTION: In a method for producing a thermoplastic elastomer compsn. used in powder molding by adding at least a hydrogenated styrene/butadiene rubber (H-SBR), a process oil and an elastomer excellent in oil absorbing capacity to a polypropylene resin with MFR (melt flow rate JIS K720) of 100-800 g/10 min and kneading these components under heating, if the melt flow properties of the polypropylene resin are improved, a compsn. excellent in melt flow properties, low in melt viscosity, excellent in tensile strength and not generating stickiness or gloss on the surface of a molded sheet by heat ageing can be obtained even if org. peroxide is not used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic elastomer composition for powder molding, which is excellent in melt fluidity required for powder molding, especially powder slush molding, has a low melt viscosity, and has excellent tensile strength. The present invention relates to a method for producing a thermoplastic elastomer composition for powder molding, which does not generate stickiness or gloss on a molded sheet surface due to heat aging.

[0002]

2. Description of the Related Art As a powder molding method using a soft powder material, a powder slash molding method using a soft vinyl chloride resin powder is used for an instrument panel, a console box,
Widely used for the skin of car interior parts such as door trim. This is a soft touch, and can be provided with leather grain and stitches, and has good design properties such as a large degree of freedom in design.

[0003] Unlike other molding methods such as injection molding and compression molding, this molding method does not apply a shaping pressure. Therefore, in order to uniformly adhere a powder material to a mold having a complicated shape at the time of molding, powder molding is performed. In some cases, the powder has excellent fluidity, so that the powder attached to the mold melts and flows even under no pressure to form a film. In addition, it was necessary that the skin formed by cooling the mold could be released more easily than the mold.

As one method for improving this, Japanese Patent Application Laid-Open No. Hei 7-82433 discloses that a polypropylene resin and a specific styrene-based thermoplastic elastomer have a weight ratio of 70/3.
It has been proposed to pulverize and use a mixture of 0 to 30/70. Here, the styrene-based thermoplastic elastomer is a styrene / ethylene / butylene / styrene block copolymer having a styrene content of 20% by weight or less, and a styrene / ethylene propylene /
It is selected from a styrene block copolymer and a hydrogenated styrene-butadiene rubber having a styrene content of 20% by weight or less, and has a good compatibility with a polypropylene resin and is a composition suitable for powder molding.

However, even with this composition, the mixture of the polypropylene resin and the hydrogenated styrene-butadiene rubber causes the hydrogenated styrene-butadiene rubber to be finely dispersed in the polypropylene resin. However, since the hydrogenated styrene-butadiene rubber has poor oil-absorbing ability, the oligomer component in the composition has migrated to the surface and has a disadvantage of having tackiness. For this reason, the thermoplastic elastomer powder pulverized for powder slush molding also has adhesiveness, so that it is easy to block and the powder fluidity is poor. In addition, when the outer skin was also released from the mold, the releasability was sometimes deteriorated.

[0006] Further, the present applicant has as an improved composition a polypropylene resin, a hydrogenated styrene-butadiene rubber, a process oil, and an organic peroxide added to an elastomer having excellent oil absorbing ability and kneaded under heating. Suggested.

[0007]

However, the organic peroxide added for the purpose of improving flowability by decomposing and chain-breaking the polypropylene resin also acts on thermal decomposition and chain-breaking of the hydrogenated styrene-butadiene rubber. However, the molecular weight of the hydrogenated styrene-butadiene rubber is reduced. Since the low molecular weight product migrated to the surface of the molded sheet, when the product was used at a high temperature, tackiness and gloss occurred on the surface.

The present invention has been made to solve the above problems, and has excellent melt fluidity required for powder molding, especially powder slush molding, low melt viscosity, excellent tensile strength, and the surface of a molded sheet due to heat aging. It is an object of the present invention to provide a method for producing a thermoplastic elastomer composition for powder molding, which does not cause stickiness or glossiness.

[0009]

That is, the invention according to claim 1 of the present application is a method for producing a thermoplastic elastomer composition used for powder molding, wherein the MFR (melt flow rate JIS K7210) is 100 to 800 g. / 10 minute polypropylene resin, at least hydrogenated styrene butadiene rubber (H-SBR), process oil,
In the method for producing a thermoplastic elastomer composition for powder molding in which an elastomer having excellent oil absorbing ability is added and kneaded under heating, if the melt fluidity of the polypropylene resin is improved, an organic peroxide is used. Even without this, it is possible to obtain a molded sheet having excellent melt fluidity, low melt viscosity, excellent tensile strength, and without generation of stickiness or gloss on the surface of a molded sheet due to heat aging.

In the invention according to claim 2 of the present application, the polypropylene resin having an MFR of 100 to 800 g / 10 min is prepared by adding an organic peroxide to the polypropylene resin having an MFR of less than 100 g / 10 min in advance of 0.02 to 5.0. A method for producing a thermoplastic elastomer composition for powder molding which is obtained by adding parts by weight and kneading under heating, in which an organic peroxide is previously added to a polypropylene resin to reduce the molecular weight. By using, it is possible to obtain a molded sheet having excellent melt fluidity, low melt viscosity, excellent tensile strength, and free of stickiness and gloss on a molded sheet surface due to heat aging.

The invention according to claim 3 of the present application relates to a method for producing a thermoplastic elastomer composition used for powder molding, wherein an organic polymer is used as a polypropylene resin having an MFR of less than 100 g / 10 minutes and an elastomer having an excellent oil absorbing ability. Oxide to 0.
02 to 5.0 parts by weight, kneading under heating, and then adding at least H-SBR and process oil and kneading under heating. By kneading the styrene-butadiene rubber and the organic peroxide without adding them at the same time, the HS
It is possible to avoid a reduction in the molecular weight of BR and prevent migration to the surface of the molded sheet due to heat aging.

The invention according to claim 4 of the present application relates to a method for producing a thermoplastic elastomer composition for use in powder molding, wherein a polypropylene resin of less than 100 g / 10 minutes, an elastomer having excellent oil absorption ability, and an organic solvent are used. A method for producing a thermoplastic elastomer composition for powder molding in which a peroxide is added in an amount of 0.02 to 5.0 parts by weight, kneaded under heating, and then at least H-SBR and a process oil are added and kneaded under heating. In particular, by kneading without simultaneously adding H-SBR and an organic peroxide, it is possible to avoid a reduction in the molecular weight of H-SBR and to prevent transfer to the surface of a molded sheet due to heat aging.

[0013] The invention according to claim 5 of the present application is a method for producing a thermoplastic elastomer composition for powder molding, in which 20 to 250 parts by weight of an elastomer having excellent oil absorbing ability is mixed with 100 parts by weight of H-SBR.

According to the invention of claim 6 of the present application, the elastomer having excellent oil absorbing ability is made of styrene, ethylene propylene,
Styrene block copolymer (SEPS), styrene / ethylene butylene / styrene block copolymer (SEB)
S), production of a thermoplastic elastomer composition for powder molding, which is at least one polymer selected from olefin crystal / ethylene butylene / olefin crystal block copolymer, ethylene propylene rubber, and ethylene / octene copolymer (POE) In the way.

[0015] The invention according to claim 7 of the present application is a method for producing a thermoplastic elastomer composition for powder molding, wherein the elastomer having excellent oil absorbing ability is an ethylene-octene copolymer having a long-chain branched structure.

The invention according to claim 8 of the present application is a method for producing a thermoplastic elastomer composition for powder molding, wherein 5 to 200 parts by weight of a process oil is mixed with 100 parts by weight of an elastomer having excellent oil absorbing ability.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene resin used in the present invention may be either a polypropylene homopolymer, a block with α-olefin or a random copolymer, and particularly a block or random copolymer using ethylene as α-olefin. Polymers are preferred from the viewpoint of the flexibility of the molded article. Further, in order to use the powder slush molding without applying pressure, the melt flowability index of the polypropylene resin is 230 ° according to JIS K7210.
It is necessary that the MFR (melt flow rate) measured at a load of 2.16 kgf at C is 100 to 800 g / 10 min. The polypropylene resin having the above MFR value has good melt fluidity, excellent melt fluidity without using an organic peroxide, low melt viscosity, excellent tensile strength, and heat aging on the molded sheet surface. It is possible to obtain a product having no sticky gloss.

When a polypropylene resin having an MFR value of less than 100 g / 10 minutes and lacking in melt fluidity is used, 0.02 to 5.0 parts by weight of an organic peroxide is added.
Knead at a temperature of 120 to 250 ° C. to obtain an MFR value of 100
The molecular weight of the polypropylene resin can be reduced so as to be ~ 800 g / 10 minutes.

When a polypropylene resin having an MFR value of less than 100 g / 10 minutes and lacking melt flowability is used, an organic peroxide is added to the polypropylene resin and melt-kneaded at a temperature of 120 to 250 ° C. After that, HS
BR can be melt-kneaded. When H-SBR and an organic peroxide are simultaneously melt-kneaded, H-SBR has a low molecular weight and migrates to the surface of a molded sheet, and after heat aging, tackiness and gloss occur on the surface.

As the above-mentioned organic peroxide, usually, rubber,
Diacyl peroxide used for crosslinking of resin,
Peroxyester, diallyl peroxide, di-t
-Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2.5-dimethyl-
2.5-di (t-butylperoxy) -hexane-3,
1,3-bis (t-butylperoxy-isopropyl)
Benzene, 1,1-di-butylperoxy-3,3,5
-Trimethylcyclohexane and the like;
Those having a half-life of 150 to 250 ° C. per minute are preferred.

In the process of kneading under heating at 120 to 250 ° C., the organic peroxide cuts the main chain of the polypropylene resin to reduce the molecular weight, and gives the thermoplastic elastomer composition high melt fluidity. The amount of the organic peroxide to be added is 0.02 to 5.0% by weight in the thermoplastic elastomer composition. When the amount is less than 0.02% by weight, the decomposition ability to cut the main chain of the polypropylene resin is small, High melt fluidity cannot be imparted to the thermoplastic elastomer composition. On the other hand, if the content exceeds 5.0% by weight, the decomposition becomes excessive and the mechanical properties such as the tensile strength of the powder molded product are reduced.

Further, H-SBR has excellent compatibility with the polypropylene resin, and when kneaded with the polypropylene resin, it becomes flexible, and a thermoplastic elastomer composition which is hardly bent or whitened can be obtained. The styrene content of H-SBR is preferably 30% by weight or less, and 5 to 15% by weight is appropriate for obtaining a flexible skin. H-SBR is different from SEBS, which is a block copolymer, in that styrene-butadiene rubber in which styrene and butadiene are randomly copolymerized is hydrogenated. A typical example is the Dynalon series, a product made by Nippon Synthetic Rubber Co., Ltd. The mixing amount of the polypropylene resin and H-SBR is in a ratio of 80/20 to 20/80 by weight. When the amount of the polypropylene resin increases, the molded skin becomes hard, and when the amount decreases, the tensile strength decreases.

In the present invention, the addition of the process oil has the effect of lowering the melt viscosity by being absorbed by the elastomer component in the composition, lowering the hardness of the skin, and providing flexibility. The above process oils are used for rubber, and include paraffinic, naphthenic,
Although classified as aroma-based, paraffin-based is preferred due to compatibility with the elastomer component. The addition amount is preferably 5 to 200 parts by weight based on 100 parts by weight of the elastomer having excellent oil absorbing ability. If it exceeds 200 parts by weight, the tensile properties are reduced, and if it is less than 5 parts by weight, the melt viscosity does not decrease and the skin becomes hard.

The elastomer having excellent oil absorbing ability is compatible with a polypropylene resin and has a property of absorbing a process oil and an oligomer component in a composition. The elastomer has a styrene-ethylene-butylene-styrene block copolymer (SEBS). ) And styrene-based block copolymer thermoplastic elastomers such as styrene-ethylene propylene-styrene block copolymer (SEPS), olefin crystal / ethylene butylene / olefin crystal block copolymer (CEBC), ethylene propylene rubber (EP
R), and ethylene-octene copolymer (POE).

In particular, the above POE is a catalyst mainly composed of a metallocene compound, having one reactive site (site) per molecule (single) and a polymer obtained by using a single-site catalyst having a homogeneous active species. It has a long-chain branched structure, a narrow molecular weight distribution, a uniform composition distribution, and a low content of low molecular weight oligomers and waxes. Therefore, when blended with a polypropylene resin, EPDM (ethylene / propylene / non-conjugated diene copolymer) has better fluid dispersibility and is more easily dispersed in the polypropylene resin than EPDM.
It becomes a material suitable for slush molding. In addition, the POE
Is different in molecular structure from a linear one polymerized by an ordinary Ziegler-Natta catalyst, for example, a general-purpose ethylene propylene rubber obtained by copolymerizing ethylene and propylene.

The above SEBS is obtained by hydrogenating a styrene / butadiene / styrene block copolymer (SBS), and includes Clayton G series, a product of Ciel Chemical Co., Ltd., and Tuftec H series, a product of Asahi Kasei Corporation. No. In this SEBS, the strength increases as the styrene content increases, but the flexibility decreases. Also,
In the case of the SEBS, the styrene hard segments may be aggregated due to melting at the time of slush molding, and it may be difficult to obtain a smooth sheet-like molded body. Therefore, the styrene content is preferably 40% by weight or less.

SEPS is obtained by hydrogenating styrene / isoprene / styrene block copolymer (SIS).
Septon, a product made by Kuraray Co., is representative. SE
As in the case of BS, the styrene content is preferably 40% by weight or less because the flexibility decreases as the styrene content increases.

The above-mentioned elastomer having excellent oil absorbing ability is
Compared with H-SBR, the compatibility with the polypropylene resin is inferior, and when kneaded and added to the polypropylene resin, it is dispersed in a size of μm unit, so that the tensile properties tend to decrease. However, the HS
When BR and process oil are added, H-SBR
Is poor in oil-absorbing ability, so that the oligomer component in the composition migrates (bleeds) to the surface and has tackiness, and the elastomer powder crushed for powder slush molding using this also has tackiness, so it is easy to block. Powder flow,
In addition, the skin also lacks releasability from the mold. When an elastomer having an excellent oil-absorbing ability is added thereto, the bleed can be prevented by absorbing the oligomer component and the oil in the composition.

The addition amount of the elastomer having excellent oil absorbing ability is 20 to 250 parts by weight based on 100 parts by weight of H-SBR. If the amount is less than 20 parts by weight, the oligomer component and oil in the composition cannot be sufficiently absorbed, and
If the amount exceeds 0 parts by weight, the dispersion with the polypropylene resin becomes poor, and the tensile properties tend to decrease.

As the heat stabilizer, those used for ordinary polyolefins can be used. Generally, phenol and a phosphorus-based antioxidant are used in combination, but are not particularly limited. As the light stabilizer, a hindered amine or benzotriazole type radical scavenger may be used. Organic and inorganic pigments suitable for ordinary olefins are used. Further, a lubricant such as a fatty acid metal salt and a filler such as calcium carbonate and talc are added as required.

The mixture of these compounds is melt-kneaded by the following four methods. (1) MFR (Melt flow rate JIS K721)
H), 100-800 g / 10 min of H-SBR, process oil, an elastomer having excellent oil absorbing ability, etc. are simultaneously added to the polypropylene resin.
This is a method of kneading at a temperature of 0 ° C. In this case, no organic peroxide is added.

(2) An organic peroxide is previously added to a polypropylene resin having an MFR of less than 100 g / 10 min.
H-SBR, a process oil, an elastomer having excellent oil absorbing ability, etc. are simultaneously added to a polypropylene resin having an MFR adjusted to 100 to 800 g / 10 minutes by adding 0 parts by weight and kneading at a temperature of 120 to 250 ° C. Add these and add 1
There is a method of kneading at a temperature of 20 to 250 ° C.

(3) 0.02 to 5.0 parts by weight of an organic peroxide is added to a polypropylene resin having an MFR of less than 100 g / 10 min and an elastomer having an excellent oil absorbing ability.
After kneading at a temperature of 50 ° C., there is a method in which H-SBR and process oil are further added thereto and kneaded at a temperature of 120 to 250 ° C.

(4) 0.02 to 5.0 parts by weight of an organic peroxide is added to a polypropylene resin having an MFR of less than 100 g / 10 min, an elastomer having excellent oil absorbing ability, and a process oil. After kneading at a temperature, H-SBR and process oil are further added to the mixture, and
There is a method of kneading at a temperature of 250 ° C.

The additive kneading method is as follows.
Dry blended using a tumbler, Henschel mixer, etc., is supplied from a raw material supply hopper, process oil is injected from a vent port, and melt-kneaded with a twin-screw extruder adjusted to a temperature in a range of 120 to 250 ° C. and pelletized. Become

[0036] The elastomer component H- is mixed with a kneader or a Banbury mixer as an internal mixer.
A process oil is added to an SBR and an elastomer having excellent oil absorbing ability, kneaded and pelletized, and then the pellet is dry-blended with a polypropylene resin to form a pellet.
Pellets can also be formed by melt-kneading with a single-screw or twin-screw extruder whose temperature has been adjusted to 50 ° C.

MFR which is the melt viscosity of the obtained pellet
Is preferably 5 g / 10 minutes or more. If it is less than this, the melt fluidity of the composition tends to be low, and pinholes tend to occur in the skin.

The pellets obtained from the above composition are pulverized using an impact type pulverizer such as a turbo mill, a pin mill, and a hammer mill. At this time, it is usually frozen and pulverized using liquid nitrogen. Further, depending on the composition, the molten resin can be powderized by spraying or cooling with a spray or disk atomizer. The pulverized material is passed through a sieve having a particle size of at least 1,000 μm by means of a sieve or the like, and those having an average particle size of 100 to 800 μm are collected. And used for powder slush molding.

Next, powder slush molding is performed using the elastomer composition. In this molding, the composition is mainly dropped by gravity and poured into a mold heated to a temperature higher than the melting point of the composition, and after a certain period of time, the mold is inverted and excess composition is collected in a collection box. The composition adheres as a layer to the mold surface, and melts over time to form a skin layer.
Then, the mold is cooled and the skin layer is released,
This is repeated.

As a heating method of the mold, a method of circulating the oil or putting it into a hot blast stove is generally used. Oil circulation is easy to adjust the mold temperature by pipe arrangement, but is heated only from the mold surface. On the other hand, when a hot blast stove is used, heating can be performed from both sides of the mold surface and the back surface of the molded product. It is necessary to consider the prescription and conditions so as not to cause oxidative deterioration.

The hot air system is effective when powder slush molding is performed in multiple layers (two or three). That is, the first powder to be the outermost layer is slush-molded in a heated mold,
The powder is deposited a second time in a semi-molten state and, if necessary, slushed a third time, then heat melted. In this case, if the heating is performed only from the mold surface side, the heat transfer is insufficient, so that a hot blast stove method capable of heating from the back surface of the molded product is often used.

[0042]

Next, the present invention will be described in more detail with reference to specific examples. Examples 1 to 4 and Comparative Examples 1 to 3 In Examples 1, 2 and 3, the polypropylene resin, H-SBR, an elastomer having excellent oil absorbing ability, a stabilizer, a release agent, and a lubricant were dried with a tumbler. The blended product was supplied from a raw material supply hopper of a twin-screw extruder (PCM45, manufactured by Ikegai Iron & Steel Co., Ltd.), kneaded at 210 ° C. and 200 rpm while process oil was injected from a vent port, and extruded into pellets.

In Examples 3, 4 and Comparative Example 2, kneading was carried out twice with a twin-screw extruder, and the materials in parentheses in the parts by weight in the table were added at the second time. It is kneaded. The first kneading condition was 10 minutes at 220 ° C.
0 rpm, and the second time is 300 rpm at 200 ° C.
It is. The above-mentioned pellets immersed in liquid nitrogen are put into a Turbomill T250-4J (manufactured by Turbo Kogyo) and pulverized,
Only the 1,000 μm sieve pass was collected.

Next, powder slush molding was performed using the above powder composition. As a method of powder slush molding, first, a 150 mm × 150 mm ×
A 3 mm plate was heated in an oven at 250 ° C., and about 800 g of the above powder composition was placed thereon for 10 minutes to be adhered.
The mixture was heated in an oven adjusted to ° C for 60 seconds, taken out of the oven and cooled with water, and the epidermis having a thickness of about 0.8 mm was removed.

The following methods were used to evaluate the melt viscosity of the pellets, the tensile properties of the skin, the tensile properties after heat aging, the presence or absence of adhesion and gloss on the surface of the skin, and the presence or absence of pinholes on the surface of the skin. Table 1 shows the obtained results.

The melt viscosity of the pellet was measured according to JIS K7210.
The melt flow rate was measured at 250 ° C. under a load of 0.325 kgf.

For the tensile properties, the skin obtained by slush molding was punched out with a JIS No. 3 dumbbell, and the tensile speed was 200 m.
The tensile strength and elongation were measured at m / min.

Regarding the tensile properties after heat aging and the presence or absence of adhesion and gloss on the surface of the skin, the surface of the skin was heat-aged for 200 hours in an oven adjusted to 120 ° C. Judged visually superiority or inferiority.光 沢 indicates that no gloss was observed on the surface, Δ indicates that some were observed, and x indicates that no surface was observed. In addition, the presence or absence of pinholes on the surface of the skin was visually judged to be superior or inferior, and those with no gloss on the surface were rated as 、, those with some gloss were rated as Δ, and those with no gloss were rated as x. These results are also shown in Table 1.

[0049]

[Table 1]

As a result, in Examples 1 to 4, the melt viscosity of the pellets was high, the flowability was high, the tensile properties of the skin after heat aging were maintained, and the surface and the surface of the skin were tacky and glossy. No pinholes were found and no pinholes were found.

[0051]

As described above, in the invention described in each claim of the present application, at least H-SBR, a process oil, and an elastomer having excellent oil absorbing ability are added to a polypropylene resin having an MFR of 100 to 800 g / 10 minutes. In the method for producing a thermoplastic elastomer composition for powder molding in which these are kneaded under heating, if the melt fluidity of the polypropylene resin is improved, the melt fluidity is excellent without using an organic peroxide. A molded sheet having a low melt viscosity, excellent tensile strength, and having no adhesive gloss on the surface of the molded sheet due to heat aging.

An organic peroxide is added to a polypropylene resin having an MFR of less than 100 g / 10 minutes in advance of 0.02 to 5.
0 parts by weight and kneaded at a temperature of 120 to 250 ° C. to reduce the MFR to 100 to 800 g / 10 min. A low molecular weight polypropylene resin can also be used, and an organic peroxide is added to the polypropylene resin in advance. By using a material having a reduced molecular weight, it is possible to obtain a molded sheet having excellent melt fluidity, low melt viscosity, excellent tensile strength, and having no gloss on the molded sheet surface due to heat aging.

Further, 0.02 to 5.0 parts by weight of an organic peroxide was added to a polypropylene resin and an elastomer having excellent oil absorbing ability, and kneaded at a temperature of 120 to 250 ° C.
A method for producing a thermoplastic elastomer composition for powder molding in which at least H-SBR and a process oil are added and kneaded under heating;
To 5.0 parts by weight, kneading at a temperature of 120 to 250 ° C., adding at least H-SBR and process oil, and kneading the mixture under heating. In particular, by kneading the H-SBR and the organic peroxide without adding them at the time, it is possible to avoid a reduction in the molecular weight of the H-SBR and prevent the transfer to the surface of the molded sheet due to heat aging.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Yoshihide Okazawa 4-1-1, Hamazoe-dori, Nagata-ku, Kobe Mitsuhoshi Belt Co., Ltd.

Claims (8)

[Claims] 1. A method for producing a thermoplastic elastomer composition for use in powder molding, comprising: a polypropylene resin having an MFR (melt flow rate JIS K7210) of 100 to 800 g / 10 minutes, at least a hydrogenated styrene butadiene rubber; A process for producing a thermoplastic elastomer composition for powder molding, comprising adding a process oil and an elastomer having an excellent oil absorbing ability and kneading them under heating. 2. A polypropylene resin having an MFR of 100 to 800 g / 10 min.
The method for producing a thermoplastic elastomer composition for powder molding according to claim 1, which is obtained by adding 5.0 parts by weight and kneading the mixture under heating. 3. A method for producing a thermoplastic elastomer composition for use in powder molding, comprising: a polypropylene resin of less than 100 g / 10 minutes and an elastomer having excellent oil absorbing ability containing an organic peroxide of 0.02 to 5.0. A method for producing a thermoplastic elastomer composition for powder molding, which comprises adding at least one part by weight, kneading the mixture under heating, adding at least a hydrogenated styrene-butadiene rubber and a process oil, and kneading the mixture under heating. 4. A method for producing a thermoplastic elastomer composition for use in powder molding, comprising: a polypropylene resin having an MFR of less than 100 g / 10 minutes; an elastomer having excellent oil absorbing ability; 02-5.0
A method for producing a thermoplastic elastomer composition for powder molding, which comprises adding at least one part by weight, kneading the mixture under heating, adding at least a hydrogenated styrene-butadiene rubber and a process oil, and kneading the mixture under heating. 5. An elastomer having an excellent oil-absorbing ability is used in an amount of 20 to 2 parts by weight per 100 parts by weight of hydrogenated styrene-butadiene rubber.
The method for producing a thermoplastic elastomer composition for powder molding according to claim 1, wherein 50 parts by weight are mixed. 6. An elastomer having excellent oil absorbing ability is a styrene / ethylene propylene / styrene block copolymer (S)
EPS), styrene / ethylene butylene / styrene block copolymer (SEBS), olefin crystal / ethylene butylene / olefin crystal block copolymer, ethylene propylene rubber, and ethylene / octene copolymer (POE) The method for producing a thermoplastic elastomer composition for powder molding according to claim 5, which is a polymer of the following. 7. The thermoplastic elastomer composition for powder molding according to claim 1, wherein the elastomer having excellent oil absorbing ability is an ethylene-octene copolymer having a long-chain branched structure. Method. 8. The method for producing a thermoplastic elastomer composition for powder molding according to claim 1, wherein 5 to 200 parts by weight of the process oil is mixed with 100 parts by weight of the elastomer having excellent oil absorbing ability.